One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(5,6)(7,10)(8,11)(9,12)(13,14,18,19,17,20,16,22)(15,23,26,28,25,21,24,27)(5,6)(7,10)(8,11)(9,12)(14,19)(15,24)(16,18)(20,22)(25,26)(27,28) involution — undirected(1,2,3,4)(5,7,10,6)(8,11,9,12)(14,20)(19,22)(21,23)(27,28)(5,8,10,9)(6,11,7,12)(13,15,18,26,17,25,16,24)(14,21,19,27,20,23,22,28)(5,9,10,8)(6,11,7,12)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.